Internal combustion engines, including diesel engines, gasoline engines, gaseous fuel-powered engines, and other engines known in the art exhaust a complex mixture of air pollutants. These air pollutants are composed of gaseous compounds including, among other things, the oxides of nitrogen (NOX). Due to increased awareness of the environment, exhaust emission standards have become more stringent, and the amount of NOX emitted to the atmosphere by an engine may be regulated depending on the type of engine, size of engine, and/or class of engine.
In order to comply with the regulation of NOX, some engine manufacturers have implemented a strategy called selective catalytic reduction (SCR). SCR is an exhaust treatment process where a reductant, most commonly urea ((NH2)2CO) or a water/urea solution, is selectively injected into the exhaust gas stream of an engine and adsorbed onto a downstream substrate. The injected urea solution decomposes into ammonia (NH3), which reacts with NOX in the exhaust gas to form water (H2O) and diatomic nitrogen (N2). In order for SCR to be most effective, the reductant should be injected into the exhaust gas stream in a uniformly distributed manner.
An exemplary reductant dosing system is disclosed in U.S. Patent Publication Number 2010/1039260 of Rodman et al. that published on Jun. 10, 2010 (the '260 publication). Specifically, the '260 publication discloses a fluid delivery system for supplying fluid to an exhaust stream of a power source. The fluid delivery system includes a supply manifold and a plurality of supply exit orifices fluidly linked to the supply manifold. The exit orifices are arranged in an annular configuration around the exhaust stream to allow the fluid to flow from the manifold to the exhaust stream in a uniformly distributed manner.